#include <iostream>
using namespace std;
const float PI=3.1415926;
class Circle{
private:
    float r;
    float area;
    float perimeter;
public:
Circle(float r){
    this->r=r;
    calculatearea();
    calculateperimeter();
}
void setR(){
    this->r=r;
    calculatearea();
    calculateperimeter();}
float getR()const{
    return r;}
void calculatearea(){
    area=PI*r*r;}
void showarea(){
    cout<<"area:"<<area<<endl;
}
void calculateperimeter(){
    perimeter=2*PI*r;}
void showperimeter(){
    cout<<"perimeter:"<<perimeter<<endl;
}
};
int main(){
Circle c(5.6);
c.showarea();
c.showperimeter();
}
